Correlations of Power-Law Spectral and QPO Features in Black Hole Candidate Sources

Recent studies have shown that strong correlations are observed between lowfrequency QPO`s and the spectral power law index for a number of black holecandidate sources (BHC's), when these sources exhibit quasi-steady hard x-rayemission states. The dominant long standing interpretation of QPO's is thatthey are produced in and are the signature of the thermal accretion disk.Paradoxically, strong QPO`s are present even in the cases where the thermalcomponent is negligible. We present a model which identifies the origin of theQPO's and relates them directly to the properties of a compact coronal regionwhich is bounded by the adjustment from Keplerian to sub-Keplerian inflow intothe BH and which is primarily responsible for the observed power law spectrum.The model also predicts the relationship between high and low frequency QPO'sand shows how BH's can be unique identified from observations of the softstates of NS's and BHC's.Comment: 2 pages, to be published in Proc. of International Conference on Stellar Mass, Intermediate Mass and Super Massive Black Holes, Oct. 28-31, 2003, Kyoto, Japa